Night vision devices, such as forward-looking infrared radar, are used to amplify light and allow a user to see images in very dark conditions. Night vision devices typically include a series of mirrors which must be aligned to a specific degree of accuracy in order for the devices to operate properly. A diamond-point turning (DPT) bolt-together method is often used to align these mirrors.
A typical DPT bolt-together method provides a pair of off-axis pins for positioning mirrors relative to an optical axis. This method has traditionally resulted in relatively expensive and tedious assembly alignment due to the adjustment of one or two mirrors in the latter assembly stages in order to achieve optimum wavefront quality. In addition, this method uses highly skilled personnel who understand interferometry, Zernike polynomials, and opto-mechanical principles to make the adjustments. Furthermore, alignment using this method is limited by tolerance stack-ups caused by the mirror-to-lathe fixture positioning and the mirror-to-assembly housing positioning. Thus, for applications requiring a higher degree of alignment accuracy than these tolerance stack-ups allow, the conventional DPT bolt-together methods are unsatisfactory.